HR: 1330h
AN: S52F-0173    [PDF]
TI: Relocation of Some Large far Offshore Earthquakes of Taiwan and its Aftershocks Using the Beam-Forming Method
AU: * Lai, Y
EM: s9622003@cc.ncu.edu.tw
AF: Institute of Geophysics, National Central University, Institute of Geophysics, National Central University, Chung - Li, 320 Taiwan
AU: Huang, B
EM: hwbs@earth.sinica.edu.tw
AF: Institute of Earth Sciences, Academia Sinica, Institute of Earth Sciences, Academia Sinica, P.O.Box 1-55, Nankang, 115 Taiwan
AU: Yen, H
EM: yen@earth.sinica.edu.tw
AF: Institute of Geophysics, National Central University, Institute of Geophysics, National Central University, Chung - Li, 320 Taiwan
AU: Yen, H
EM: yen@earth.sinica.edu.tw
AF: Institute of Earth Sciences, Academia Sinica, Institute of Earth Sciences, Academia Sinica, P.O.Box 1-55, Nankang, 115 Taiwan
AU: Chen, K
EM: chenkc@earth.sinica.edu.tw
AF: Institute of Earth Sciences, Academia Sinica, Institute of Earth Sciences, Academia Sinica, P.O.Box 1-55, Nankang, 115 Taiwan
AB: The Taiwan orogeny is a result of the collision of the Philippine Sea Plate and the Eurasian Plate, and therefore there is high seismicity in onshore-offshore Taiwan. The location of the earthquake inside the seismic is well resolved, however the location of the offshore earthquake far from the seismic network would be some uncertain because of its small observational aperture of seismic network. In this study the beam-forming method (Capon, 1973) is used to relocate the epicenters of some large events to determine its high resolution of source parameters and to discuss its tectonic implications. We will determine three large earthquake sequences far from Taiwan offshore. One is the 16 September 1994 earthquake occurred in the Taiwan Strait where is situated west on the Taiwan island with a low seismicity. This event is the largest event in this area in modern history. Another eastern Taiwan offshore earthquake occurred on 3 May 1998 with a magnitude of 7.5 and located in the Philippine Sea Plate, only a few small shallow events occurred. The other offshore earthquake occurred on 31 March 2002 with a magnitude of 7.0 and induced large seismic amplification in Taipei basin but not in Hualien area. Accurate locations of the main shocks and their aftershocks would help us to understand its source properties. Based on results of this study and other information, we will discuss the stress conditions of source areas and its tectonic implications.
DE: 7200 SEISMOLOGY
SC: Seismology [S]
MN: 2003 Fall Meeting